Cell unit for insertion into a flashlight



Dec. 12, 1961 w. WlTTE EFAL 3,013,198

CELL UNIT FOR INSERTION INTO AFLASHLIGHT Original Filed Sept. 5, 1957 2Sheets-Sheet l Dec. 12, 1961 w. wlTTE ETAL 3,013,198

CELL UNIT FOR INSERTION INTO A FLASHLIGHT Original Filed Sept. 5, 1957 2She etS-Sheet 2 United States Patent Ofilice 3,013,198 Patented Dec. 12,1961 5 Claims. c1. 320-2 This application is a continuation of ourapplication Serial No. 682,182, now abandoned.

This invention relates to rechargeable cell units or inserts forflashlights or the like.

By way of definition, the term cell unit or cell insort is intended todesignate a composite article which is provided with positive andnegative terminal on its exterior and with a power source proper in itsinterior and is shaped in the manner of conventional primary cellsforinsertion into the body of a flashlight to provide power for thelight bulb thereof.

One type of flashlight which has recently become known has a housing inwhich is accommodated a storage battery serving to energize the lightsource, together with a charging system or circuit for the battery andprongs for insertion into a power line socket. The charging system isgenerally so arranged that there is provided a capacitor connected inseries with a resistor which func tion as a voltage divider for reducingthe line voltage to the value required for the charging operation, thecharging voltage to be applied to the charging dry rectifier eing takenoff across the aforesaid resistor. In a refinement of this flashlight,the charging system is improved by a control arrangement in which thevoltage divider, which may comprise both active and reactive or wattlessresistances, includes in lieu of the ohmic tapping resistor anadditional dry rectifier which is connected into the circuit with itspolarity opposite to that of the charging rectifier connected inparallel therewith. In this manner, the charging rectifier is protectedagainst suddendly occurring voltage peaks.

It has now become evident that such a charging system can advantageouslybe disposed in a flashlight cell insert or unit whiclris provided with asecondary cell, preferably a small storage battery.

Small storage batteries to be inserted into the body of a flashlight areknown, but when being recharged these must usually be connected to aseparate charging device forming no part of the flashlight or any of itscomponents.

The principal object of the present invention is, thus, the provision ofa flashlight cell unit or insert comprising a casing equipped withconventionally constructed low voltage output terminals andaccommodating a rechargeable secondary cell or battery, preferably asmall storage battery, together with a charging circuit connectedthereto.

Another object of the present invention is the provision of such aflashlight cell unit which is characterized by the fact that togetherwith the rechargeable secondary battery and the charging system orcircuit there are provided in the cell unit casing means facilitatingconnection of the charging system to a supply voltage main or linewithout necessitating removal of the charging system or storage batteryfrom the casing.

A related object of the invention is, therefore, the provision of meansenabling a flashlight cell unit of the aforesaid type to be easilyconnected to any common house socket upon being removed from the body ofthe flashlight which it powers, for the purpose of charging the storagebattery. Advantageously, there are provided for this purpose connectingmeans which are so constructed that during the normal operatingcondition of the cell unit they are located interiorly of the casing orhousing thereof, while for connection to the current supply network orline during the charging operation they are rendered accessible eitherby being protracted from the housing or by being shifted away andseparated from at least one portion of said housing.

An especially advantageous and efiicacious structure according to theforegoing is attained when the line connecting means of the unit areconstructed in the form of two displaceable electric plug-like prongswhich can be slid jointly to project out of the casing or housing foruse during the charging operation.

It is still another object of the present invention to provide meansensuring absolute safety of any person using or manipulating theflashlight cell unit during a charging operation. To this end, the cellunit houses suitable control of switch means which automatically effectelectric disconnection of the exposed low voltage output terminals ofthe unit from the charging circuit and from the secondary batterywhenever the line connecting means are exposed. In this manner, alldanger of shocks due to contacting any electrically conductive part ofthe unit is eliminated since the casing thereof may be constructed ofinsulating material or may be otherwise insulated from the voltageandcurrent-conducting inner parts.

A further object of the present invention is to provide a suitableconstruction of the voltage divider of the charging system to therebyensure that even at the highest possible line voltages which may beencountered, no excessively high charging current can be generated. Aline voltage change, which may require the use of a transformer, is thusrendered unnecessary and is effectively replaced by recharging periodsof different durations.

It is a still further object of the present invention to provide apocket flashlight cell unit of the aforesaid type which is compactly andsturdily built so as to withstand shocks and other detrimentalinfluences resulting from continued use and handling over long periodsof time, and which is both easy and inexpensive to manufacture andservice.

These and other objects and advantages of the present invention willbecome more fully evident from the following detailed description whentaken in conjunction with the accompanying drawings, in which:

FIG. 1 is a side elevational view of a flashlight cell unit or insertconstructed according to the present invention and showing the lineconnecting, electric plug-like prongs in protracted position;

FIG. 2 is a top plan view of the unit shown in FIG. 1;

FIG. 3 is a circuit diagram of the control and switching arrangement forthe charging system, the prongs being shown in protracted position forcharging of the storage battery; and

FIG. 4 is a schematic illustration, partly in section, of the interiorarrangement of the parts of the flash light cell unit.

Referring now more particularly to the drawing, it will be seen that theflashlight cell unit according to the invention comprises a housing orcasing 19 into the upper end wall 19a of which are screwed two threadedbolts or like members 17a and 18a carrying, respectively, outputterminals or like low voltage connecting means constructed in the formof lugs 17 and 18 which, during use of the flashlight, are connected tothe negative and positive terminals of a small storage battery 7 alsodisposed in casing 19 and held in position by a tensioned spring clamp23. Positioned at and protruding slightly from one side casing through aslot'14a is a slidable knurled gripping member 14 which is connectedinteriorly of the casing, by means to be more fully describedhereinafter, to two electric plug-like prongs 1 and 2 designed forinsertion into any standard house line socket (not shown) and slidablyarranged in electrically consecutive guide sleeves 9 and 10,respectively, fixed to the bottom end wall 1% of the casing.

The casing 19 also houses a storage battery charging system or circuitwhich includes a protective resistance 3 connected between sleeves 9 and1t) and thus directly across the prongs 1 and 2. Connected in parallelwith the resistance 3 and in series with one another are a currentlimiting resistor 4, a reactive or wattl-ess resistance in the form of acapacitor 5, and an asymmetrical resistance in the form of a dryrectifier 6, the resistor 4, capacitor 5 and rectifier 6 constituting avoltage divider. The charging voltage to be applied to the small storagebattery 7 is taken off across the rectifier 6 via a charging dryrectifier 8 having its output terminal connected to the positive batteryterminal and its input terminal to the junction between the capacitor 5and the output terminal of the rectifier 6 which has its input terminalconnected to the negative battery terminal.

The rectifiers 6 and 8, shown in the form of dry plate rectifiers whichmay be made of selenium or like materials, are mounted on a commoncarrier 6a provided with a threaded end 24 screwed into a wall of thehousing 19. The limiting resistor 4 and the capacitor 5 are mounted andfixed in position within the housing in any suitable manner (notspecifically shown).

The sleeves 9 and 10 are provided with elongated, longitudinallyextending slots 9a and 10a, respectively. The prongs 1 and 2 areprovided with projections 11 and 12 extending through and guided by saidslots and connected to the gripping or manipulating member 14 by meansof an insulating cross bar 13. Aflixed to the inner ends of the prongs 1and 2 are small plugs or masses 21 and 22 of insulating material, whileeach of the sleeves 9 and 10 is provided on its inner surface adjacentits opposite ends with two catch members which are arranged to bereceived in correspondingly shaped recesses (not shown) formed on theProngs 1 and 2 so as to enable immobilization of the latter in theirprotracted and retracted positions.

Fixedly mounted on brackets 19c and 19d in the casing 19 are twoswitches 15 and 16 constituted, respectively, by spring contacts 15a,15b and 16a, 16b of the type employed in conventional relays. Themovable ends of the contact springs 15a and 15a are disposed adjacentthe inner open ends of the guide sleeves 9 and 10 and are adapted to bedisplaced so as to close the switches 15 and 16 by the insulating ends21 and 22 of the prongs 1 and 2 whenever the latter are pushed orretracted into the casing. The low voltage connecting means or outputterminals 17 and 18 are connected to the spring contacts 15a and 16a,respectively. The spring contact 15b is connected to sleeve 9 and prong1 and to the negative pole of the storage battery 7 as well as to oneend of the protective resistor 3 and the input terminal of the dryrectifier 6, while the spring contact 16b is connected to the positiveterminal of the storage battery and to the output terminal of thecharging dry rectitier 8.

The operation of the charging system is as follows:

During normal use of a flashlight when the cell unit is inserted in thebody of the flashlight and provides power for the bulb thereof, theprongs 1 and 2 are retracted into the housing 19. The'insulating pushbuttons 21 and 22 formed by the inner prong ends thus close the switches15 and 16, as a result of which the lugs or terminals 17 and 18 areconnected to the opposite terminals of the storage battery 7.

If it is now desired to recharge the cell unit, the housing 19 isremoved from the flashlight body and the gripping member 14 pushed alongthe slot 14a to move the prongs 1 and 2 outwardly of the housing 19.During this movement, the contacts of the switches 15 and 16 are opened,whereby the lugs 17 and 18 are electrically disconnected from thecharging system and from all of the control elements accommodated withinthe housing 19. Upon insertion of the prongs 1 and 2 into any commonhouse line socket, the line voltage is applied to the voltage divider4--56 across the discharge resistor 3. The resistor 4 limits the currentflowing in the circuit and thus prevents overloading of the same. Byvirtue of the fact that an asymmetrical resistance, i.e., the dryrectifier 6, is used in lieu of the conventional ohmic resistance, thereis attained a protection of the charging rectifier 8 against highvoltage peaks occurring suddenly in the charging circuit. The directvoltage taken off the rectifier 6 is applied through the rectifier 8 tothe storage battery 7. Upon completion of the charging operation, whichshould take at most a few hours, the prongs 1 and 2 are drawn out of thesocket and pushed back into the housing 19 by means of the grippingmember 14, whereafter the cell unit may be replaced in the flashlightfor further use.

It will be readily appreciated that various changes may be made in thecell unit according to the present invention without departing from thescope of the invention as defined in the appended claims. Thus, by wayof example, the dry-cell-shaped housing 19 may have different contoursthan as illustrated herein, while difi'erent types of switches may besubstituted for the switches 15 and 16.

What is claimed is:

1. A cell unit simulating a flashlight dry cell battery for insertioninto a flashlight to provide power for the same, comprising asubstantially closed dry-cell-shaped casing, a pair of low voltageoutput terminals carried by said casing exteriorly thereof, a smallstorage battery fixedly mounted in and completely enclosed by saidcasing and having positive and negative terminals electrically connectedto said output terminals, respectively, a. charging circuit fixedlyenclosed within said casing and electrically connected to said storagebattery, and connector means mounted in said casing and electricallyconnected to said charging circuit for connecting the latter to a powerline, said charging circuit including capacitive means for reducing thepower line voltage to the value needed for charging said storagebattery, means defining a path of reciprocal movement for said connectormeans out of and into said casing, thereby to render said connectormeans accessible for connection to said power line when moved out ofsaid casing and inaccessible when moved into said casing, switch meansfor establishing the connection between said output terminals and saidstorage battery and normally closed upon movement of said connectormeans into said casing, said switch means being opened upon movement ofsaid connector means out of said casing during a charging operation toautomatically disconnect said output terminals electrically from saidstorage battery, said charging circuit and said connector means.

2. A cell unit according to claim 1, said connector means comprising apair of prongs rigidly interconnected in the manner of an electric plugto enable insertion of said prongs into any standard electric socketconnected to said power line.

3. A cell unit according to claim 2, said path defining means comprisinga pair of electrically conductive sleeves each slidably accommodating arespective one of said prongs, said sleeves being open at their oppositeends to enable said prongs to project therefrom both when moved intosaid casing and when moved out of said casing, said switch meanscomprising two pairs of relay-type spring contacts with a first contactof each pair positioned adjacent the inner open end of the associatedsleeve and in the path of movement of the corresponding one of saidprongs for displacement by the latter into engagement with the secondcontact of the same pair upon movement of said prongs into said casing.

4. A cell unit simulating a flashlight dry cell battery, comprising asubstantially closed dry-cell-shaped casing, a pair of low voltageoutput terminals carried by said casing exteriorly thereof, a storagebattery fixedly mounted in and completely enclosed by said casing andhaving positive and negative terminals, electrical connections betweenasid positive and negative battery tor-- connector means accessible forconnection to said power line when extending out of said casing andinaccessible when "enclosed within said casing, circuit breaker means inthe connections between said output terminals and said storage batteryterminals, said circuit breaker means being responsive to said movablemeans for automatically connecting said storage battery to said outputterminals when said connector means are enclosed in said casing.

S, A cell unit simulating a dry-cell battery, comprising a substantiallyclosed dry-cell-shaped casing, a pair of low voltage output terminalscarried by said casing exteriorly thereof, a storage battery fixedlymounted in and completely enclosed by said casing and having positiveand negative terminals electrically connected to said output terminals,respectively, a charging circuit fixedly enclosed within said casing andelectrically connected to said storage battery, and connector meansmounted in said casing and electrically connected to said chargingcircuit for connecting the latter to a power line, said charging circuitincluding means for rectifying and reducing the power line voltage tothe value needed for charging said storage battery, said cell unitincluding means for exposing said connector means or enclosing themwithin said casing, thereby to render said connector means accessiblefor connection to said power line when extending out of said casing andinaccessible when enclosed within said casing, and connecting meanslocated between at least one of said exterior output terminals and saidstorage battery responsive to said exposing and enclosing means forconnecting said storage battery to said one output terminal when saidconnector means are enclosed in said casing References Cited in the fileof this patent UNITED STATES PATENTS

